Where are you putting your inline fuel filter?

[b5blue]

 I want to add a 3/8 inline filter, preferably between the fuel line and the pump. Think it's okay to filter on the suction side of a Carter M6903 or must it be on the pressure side?   

[fy469rtse]

I put one in both positions ,
before pump,
you want any crap stopped at filter before it gets to pump,
second one in between pump and carby to stop and filter anything that gets past pump 

[justcruisin]

I use that pump, I just have one quality filter of 40 microns mounted pre-pump, on one occasion I have had a hair block an idle feed restrictor. Two filters is probably a good idea.

[fy469rtse]

And I use the transparent ones,
So at a glance you can tell if it needs changing 

[b5blue]

Thanks I've got a good spot in mind just before the pump.  

[b5blue]

Here's what I did.

[johnnycharger]

Here's what I did.

Looks good. Can please post pictures of the rest of the line heading to the carburetor?

[b5blue]

I can later but right now it's just 3/8 rubber hose with a tee to each side of the carb. I'm getting ready for test/tune.

[BSB67]

The factory had only one filter and one works fine.  They belong on the pressure side of the pump. A far smaller restriction on the suction side will give you problems.  Mechanical pump don't need a filter on the suction side.

[Paul G]

I am only using one filter on the pressure side of the mechanical pump as well. Small particles will get go right through the pump, catch them in filter before it gets to the carb. I have read that pumps dont do well with restrictions on the suction side. They are designed to push, they dont do a very good job of pulling fluid past a restriction. I mounted the filter on the frame rail next to the pump.

[six-tee-nine]

Neal,

I know from your posts that you Always think things trough well before executing them. I however have a remark.

Is there enough flex in the line before the filter? In other words is the hose between the filter and the steel line to the tank long enough?  You must take in consideration that under heavy acceleration the engine flex is quite a bit and if the hose before the filter is just as long as the one in between the filter and the pump I might see a potential problem there.

There's nothing wrong with putting a loop or an extra bend in the fuel line to give it some extra slack.....

[A383Wing]

I put all mine before the pump...and made a one piece bent solid one piece line from pump to carb, this way there is no rubber hose blow-out and fuel pumped all over the place....filter protects the pump as well....plus it's easier to get to then behind the alternator....

[b5blue]

Neal,

I know from your posts that you Always think things trough well before executing them. I however have a remark.

Is there enough flex in the line before the filter? In other words is the hose between the filter and the steel line to the tank long enough?  You must take in consideration that under heavy acceleration the engine flex is quite a bit and if the hose before the filter is just as long as the one in between the filter and the pump I might see a potential problem there.

There's nothing wrong with putting a loop or an extra bend in the fuel line to give it some extra slack.....

Thanks for that comment and concern 69! My motor is chained down, one end welded to the K Frame, it can't move much. My 3/8th fuel line isn't stock there is about 6" of hose between it and the filter. That filter isn't staying long, it's a systems check to see if any crap is coming to the pump. New lines and tank/pickup are in the works but between disk swap and intake/carb/fuel pump swap I ran out of $$$ and time!  I positioned the filter where I can see it by lifting the hood or looking up from under the car very easy. It shouldn't be getting any crap, my pickup sock and tank were all checked and good a few years ago. 

[BSB67]

Found this

"Choose & Position the Right Filters
Fuel filter type and placement are critical to achieving the proper fuel pressure and volume being delivered to the carburetor. A high-flow, fine-element fuel filter should be used between the fuel pump and carburetor on the pressure side, not between the tank and the pump on the suction side. Between the tank and the pump you'll want to run a coarse-filter screen no finer than 100-micron. This is because as a pump pushes, it also has to pull, and when a pump has to pull too hard to acquire fuel through a restrictive filter, a vacuum or low-pressure area develops at the inlet. To be sure of the specs for your fuel filter, always check with the fuel pump's manufacturer for a recommendation. A more restrictive filter on the suction side of the pump may fail to flow the full volume of the pump, which can result in cavitation at the pump inlet."

From the internet....take it for what it is worth......

[A383Wing]

I have had the filter on the suction side since 1974....no issues ever

from my garage, take it for what it's worth....

[BSB67]

If you make enough power, that inline filter will cause a fuel delivery problem.  If you don't, you'll never know the difference.  Certainly not a problem driving around town.  Fuel starvation can go unrecognized but the engine will simply underperform under WOT and the owner either does not know any different, or does not figure it out. 

I have used suction side filters that were designed for suctions side.  I wonder why the suction side filters are designed differently than the pressure side filters?  Those silly automotive companies.

Six months from now he might be posting how the car is lazy on the top end.  There will be a hundred post from anything from the cam was not degreed right to he needs more gear.  I have seen this more than once due to fuel suction side restriction. 

[b5blue]

My thinking is the sock for the fuel pickup is the first filter.

[Dino]

My thinking is the sock for the fuel pickup is the first filter.

It is, I'm just not sure of the particle size it stops.

I need to mount a filter on the hardline between pump and carb, I'm only running the vapor separator right now.

[68 RT]

There should be a filter in the carb fuel line inlet. Either paper or brass, the brass ones are washable. Undo your fuel line then unscrew the big nut. There is a spring behind it so it will pop out.

[A383Wing]

There should be a filter in the carb fuel line inlet. Either paper or brass, the brass ones are washable. Undo your fuel line then unscrew the big nut. There is a spring behind it so it will pop out.

never seen that on an AFB or AVS carb......GM carbs, yes....but not our cars...would like to see a pic of one if you have it

[68 RT]

Here's the original Carter AVS off my 440. Dino just remembered you have a thermoquad. They may not have one? But not sure.

[Dino]

Here's the original Carter AVS off my 440. Dino just remembered you have a thermoquad. They may not have one? But not sure.

The TQ does not have one no, but I think the Edelbrocks have a filter.  I think I can fit a short filter on the short rubber hose running from the vapor separator to the carb hard line.  That oughta do it!